The diversity of birds helps them survive by the differences in their beaks the different shapes and sizes means they all eat different food therefore that is not an issue. Different coloration is not an issue due to the species separating from each other. The diversity keeps the birds alive by signifying differences.
Hope this helps!
The author credited with launching the English romantic movement was "William Wordsworth" especially with his masterpiece "The Prelude", although it should be noted that there several other prominent, early romantic writers.
Assuming you're referring to Frederick Lucas, he says that the preamble to the Declaration of Independence "sets the tone" for the rest of the document by making it clear why exactly the founders have submitted it.
To have some fun and not be bored all the time